Not just GY welting. Dissect your C&J and observe what's been used inside and compare to what's used inside Vass/St Crispins/bespoke shoes of various refinements. Heat formed stiffeners? Checked. Canvass lining? Checked. Thin insoles? Checked. Pick your own poison.
Owned both Meermin LM & C&J Handgrade, I like Meermin better. And they costs about the same prior to the skyrocketing price increases of C&J for the past several years.
p.s., Meermin LM insole is about 3.5-4mm thick, about 7 irons. Some bespoke makers goes as thick as 10 irons for insole...
I'll just note that I have several pairs of C&J, both in benchgrade and handgrade form, and all of them are leather-lined. I've never seen a pair of C&Js with fabric lining and I wouldn't buy them if they were fabric-lined.